[WIP] Micro Runtime (#947)

* Add Get() and GetOptions.

* Removed watcher. Outline of client. YAML templates

* Added default service and deployment templates and types

* Added API tests and cleaned up errors.

* Small refactoring. Template package is no more.

* Ripped out existing code in preparation to small rework

* Reshuffled the source code to make it organized better

* Create service and deployment in kubernetes runtime

* Major cleanup and refactoring of Kubernetes runtime

* Service now handles low level K8s API calls across both K8s deployment
an service API objects
* Runtime has a task queue that serves for queueing runtime action
requests
* General refactoring

* No need for Lock in k8s service

* Added kubernetes runtime env var to default deployment

* Enable running different versions of the same service

* Can't delete services through labels

* Proto cruft. Added runtime.CreateOptions implementation in proto

* Removed proxy service from default env variables

* Make service name mandatory param to Get method

* Get Delete changes from https://github.com/micro/go-micro/pull/945

* Replaced template files with global variables

* Validate service names before sending K8s API request

* Refactored Kubernetes API client. Fixed typos.

* Added client.Resource to make API resources more explicit in code

runtime/default.go

@@ -21,6 +21,7 @@ type runtime struct {
 	// indicates if we're running
 	running bool
 	// the service map
+	// TODO: track different versions of the same service
 	services map[string]*service
 }
 
@@ -175,6 +176,56 @@ func (r *runtime) Create(s *Service, opts ...CreateOption) error {
 	return nil
 }
 
+// Get returns all instances of requested service
+// If no service name is provided we return all the track services.
+func (r *runtime) Get(name string, opts ...GetOption) ([]*Service, error) {
+	r.Lock()
+	defer r.Unlock()
+
+	if len(name) == 0 {
+		return nil, errors.New("missing service name")
+	}
+
+	gopts := GetOptions{}
+	for _, o := range opts {
+		o(&gopts)
+	}
+
+	var services []*Service
+	// if we track the service check if the version is provided
+	if s, ok := r.services[name]; ok {
+		if len(gopts.Version) > 0 {
+			if s.Version == gopts.Version {
+				services = append(services, s.Service)
+			}
+			return services, nil
+		}
+		// no version has sbeen requested, just append the service
+		services = append(services, s.Service)
+	}
+	return services, nil
+}
+
+// Update attemps to update the service
+func (r *runtime) Update(s *Service) error {
+	var opts []CreateOption
+
+	// check if the service already exists
+	r.RLock()
+	if service, ok := r.services[s.Name]; ok {
+		opts = append(opts, WithOutput(service.output))
+	}
+	r.RUnlock()
+
+	// delete the service
+	if err := r.Delete(s); err != nil {
+		return err
+	}
+
+	// create new service
+	return r.Create(s, opts...)
+}
+
 // Delete removes the service from the runtime and stops it
 func (r *runtime) Delete(s *Service) error {
 	r.Lock()
@@ -199,26 +250,6 @@ func (r *runtime) Delete(s *Service) error {
 	return nil
 }
 
-// Update attemps to update the service
-func (r *runtime) Update(s *Service) error {
-	var opts []CreateOption
-
-	// check if the service already exists
-	r.RLock()
-	if service, ok := r.services[s.Name]; ok {
-		opts = append(opts, WithOutput(service.output))
-	}
-	r.RUnlock()
-
-	// delete the service
-	if err := r.Delete(s); err != nil {
-		return err
-	}
-
-	// create new service
-	return r.Create(s, opts...)
-}
-
 // List returns a slice of all services tracked by the runtime
 func (r *runtime) List() ([]*Service, error) {
 	var services []*Service